Ball cock valves are float-operated valve mechanisms, principally used as flush valves in a water closet. The valves are opened responsive to the dropping of a float, usually on a lever arm, when water is discharged from a water closet, and are closed when the float is raised to a fill position in the tank. There are many different types of float-operated ball cock valves. One such design is called a "pilot-operated valve." In a pilot-operated valve, equal pressure between the inlet and a pressure chamber on opposite sides of a flexible valve element seals the valve element against a valve seat. When water is discharged from the tank, the float-operated lever arm vents the pressure chamber to open the valve element and permit the passage of water through the valve seat. When the water closet fills to an appropriate height, the vent is closed and the valve element again seals the valve seat to cut off flow of water to the tank. Examples of such pilot-operated valves are found in the following U.S. patents:
______________________________________ Weaver et al 925,538 (issued June 22, 1909) Gustafson 1,248,650 (issued December 4, 1917) McCormack 2,143,204 (issued January 10, 1939) Schoepe et al 3,429,333 (issued February 25, 1969) Schoepe et al 3,495,803 (issued February 17, 1970) ______________________________________
A pilot-operated valve for an air vent system is disclosed in the Becker et al U.S. Pat. No. 4,299,248, issued Nov. 10, 1981.
It is desirable to adjust the level to which the tank might fill. Various adjustment mechanisms have been provided. One such adjustment mechanism is disclosed in the British Secification No. 564,982 published Oct. 20, 1944. In this specification, a series of cork discs, eccentrically mounted on a supporting arm, provide the float function. Rotation of the cork discs with respect to the arm will change the level to which the arm rises in the water closet.
The patent to Steensen U.S. Pat. No. 1,756,398, issued Apr. 29, 1930, discloses a float valve for controlling the flow of water into a water tank. The float includes a hollow ball with a threaded, plugged opening for filling the ball with water to a desired level. The ball is threaded onto a lever arm.